This invention relates to a tank assembly for storing hydraulic oil in a system for actuating hydraulically operated cylinders. More specifically, this invention comprises a tank assembly for storing hydraulic fluid on Class VI, VII, and VIII trucks as applied in the heavy-duty truck market in the United States. As the hydraulic system is actuated, the pump draws hydraulic fluid from the tank for use in forcing the hydraulic cylinder, mounted under the dump trailer, into an upright position in order to discharge the commodity being transferred. As the pump valve is shifted to the down position, the hydraulic fluid returns through the system to the tank assembly for storage. This returning fluid must not be allowed to aerate; therefore, the velocity of the returning hydraulic fluid must be reduced without reducing the rate of flow in gallons per minute below the rated pump capacity at 1000 rpms.
Prior storage systems use both conventional metal and molded polyethylene reservoirs as storage components for the hydraulic fluid. Each of these systems have inherent problems troubling to the product user. Conventional metal reservoirs have welded seams which, depending on the skill of the welder, can leak or leave a metal slag residue. These contaminants, such as slag, sands, and rust, range in the 100-200 micron size. This size contaminant causes problems because high pressure hydraulic components cannot pass particles larger than 10 microns without eventual destruction to the system.
Prior molded polyethylene reservoirs have addressed and corrected the contamination problems inherent in the fabricated metal reservoirs; however, three distinct problems have arisen with the use of the molded reservoirs: 1) annoying leaks at the junction where the metal port fitting is molded into the polyethylene; 2) tank distortion caused by the occasional heat build-up in the hydraulic system and consequently the hydraulic fluid stored in the reservoir; and 3) inadequately providing for a convenient and effective procedure for diffusing hydraulic fluids as they are returned to the storage reservoir or tank.